# 编写一个函数，其作用是将输入的字符串反转过来。输入字符串以字符数组 s 的形式给出。

# 不要给另外的数组分配额外的空间，你必须原地修改输入数组、使用 O(1) 的额外空间解决这一问题。

 

# 示例 1：

# 输入：s = ["h","e","l","l","o"]
# 输出：["o","l","l","e","h"]
# 示例 2：

# 输入：s = ["H","a","n","n","a","h"]
# 输出：["h","a","n","n","a","H"]
 
class Solution:
    def reverseString(self, s: list[str]) -> None:
        """
        Do not return anything, modify s in-place instead.
        """
        i,j = 0, len(s)-1
        while i <= j:
            s[i], s[j] = s[j],s[i]
            i += 1
            j -= 1